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In microcrystal samples of the prototypical organic molecular semiconductors rubrene and C10-DNTT (2,9-didecyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene), we measured spectra of complex optical conductivity caused by photocarriers with optical-pump terahertz-probe spectroscopy. We analyzed the σ ω spectra using the Drude-Smith model and evaluated the DC mobility μ DC, which includes extrinsic effects, and the intrinsic mobility μ int. The resulting μ DC and μ int values are comparable to the mobility values obtained using transport measurements of polycrystalline and single-crystalline field-effect transistors, respectively. This correspondence demonstrates that the intrinsic mobility values of organic molecular semiconductors can be evaluated from the measurements of microcrystal samples using transient terahertz spectroscopy.

Ultra-fast coherent magnetization reversal, which is indispensable for high-speed spintronic devices, is expected to be realized by irradiation with a nearly monocyclic terahertz pulse. In this letter, using MnAs ferromagnetic nanoparticles embedded in a GaAs host matrix, we observe a large modulation up to 20% of the magnetization of these nanoparticles with terahertz pump pulse irradiation. This modulation ratio is the largest value ever reported for terahertz magnetization modulation. We reveal that the modulation is induced by the electric-field component of the terahertz pulse via spin-carrier interactions. Ferromagnetic nanoparticle systems are promising, and material designing is the key for ultrafast magnetization reversal using terahertz pulses.

The design and performance of an ultrahigh vacuum compatible cryogenic dual-tip scanning tunneling microscope is described. The microscope is attached at the bottom of a low-loss liquid helium Dewar and can be operated down to 4.2 K. The coarse positioning system consists of five linear steppers driven by piezo-tubes. The displacement of each stepper can be monitored by its own embedded capacitive position sensor with a submicron resolution, thus allowing accurate control of the tip navigation process. An alignment procedure, using a specimen made of three mutually nonparallel planes, is introduced to bring the two tips into overlapped scan ranges without the help of an additional guiding device such as an electron microscope. The overall system exhibits good mechanical rigidity and atomic resolution has been achieved with either tip. This instrument is well suited for investigating low temperature quantum properties of atomically clean nanostructures in a three-terminal configuration.

The one-dimensional Cu–O chains responsible for the large optical nonlinearity in Sr2CuO3 (SCO) and Ca2CuO3 (CCO) are aligned in one direction in films grown on LaSrAlO4 (LSAO) (1 0 0) substrates by using pulsed laser deposition. The CCO films deposited directly on lattice matched LSAO substrates have a single orientation with high crystallinity, while the SCO films include small portions of misoriented domains. Using a simple model of lattice mismatch, we developed a Sr2TiO4 buffer layer in order to grow orientation-controlled SCO films with both high crystallinity and a sharp optical absorption edge. This technique will be a key to fabricating ultrafast all-optical switches with a waveguide structure.

A design of a microspectrophotometric system using a synchrotron radiation (SR) source is described. The system covers a wide spectral range of 50–13000 cm−1, being under construction at the UVSOR BL6B beamline in the Institute for Molecular Science. Preliminary experiments in the mid‐infrared region (500–5000 cm−1) have qualitatively confirmed the theoretical calculation that the synchrotron radiation is more intense than a blackbody (T=1200 K) when a microspectrophotomeric technique is applied, which is due to natural collimation and high brilliance of SR source. The SR as an infrared source exhibits its advantage on measuring the spectra of small single crystals especially in the far‐infrared region.

We have investigated optical nonlinearity in low-temperature (LT) molecular-beam-epitaxy-grown GaAs/AlAs multiple quantum wells (MQWs). Minimum saturation intensity, that is, maximum optical nonlinearity, is observed at around the excitonic absorption peak. The saturation intensity of the LT MQW is smaller by an order of magnitude than that of LT bulk GaAs. The response time of the LT MQW is 1/4–1/2 of the LT GaAs, and becomes less than 1 ps, corresponding to ∼1/400 of the standard-temperature-grown MQW. These results demonstrate a clear advantage of the room-temperature excitons in the LT MQW having large optical nonlinearity as well as fast response time.

Strong parametric mode coupling in mechanical resonators is demonstrated at room temperature by using the photothermal effect in thin membrane structures. Thanks to the large stress modulation by laser irradiation, the coupling rate of the mechanical modes, defined as half of the mode splitting, reaches 2.94 kHz, which is an order of magnitude larger than electrically induced mode coupling. This large coupling rate exceeds the damping rates of the mechanical resonators and results in the strong coupling regime, which is a signature of coherent mode interaction. Room-temperature coherent mode coupling will enable us to manipulate mechanical motion at practical operation temperatures and provides a wide variety of applications of integrated mechanical systems.

Using a terahertz-radiation imaging, visualizations of ferroelectric domains were made in a room-temperature organic ferroelectric, croconic acid. In as-grown crystals, observed are ferroelectric domains with sizes larger than 50-μm square, which are separated by both 180° and tail-to-tail domain walls (DWs). By applying an electric field along c axis (the polarization direction), a pair of 180° DWs is generated and an each 180° DW oppositely propagates along a axis, resulting in a single domain. By cyclic applications of electric fields, a pair of 180° DWs repeatedly emerges, while no tail-to-tail DWs appear. We discuss the usefulness of the terahertz-radiation imaging as well as the observed unique DW dynamics.

The dynamics of photogenerated electrons and holes in undoped anatase TiO2 were studied by femtosecond absorption spectroscopy from the visible to mid-infrared region (0.1–2.0 eV). The transient absorption spectra exhibited clear metallic responses, which were well reproduced by a simple Drude model. No mid-gap absorptions originating from photocarrier localization were observed. The reduced optical mass of the photocarriers obtained from the Drude-model analysis is comparable to theoretically expected one. These results demonstrate that both photogenerated holes and electrons act as mobile carriers in anatase TiO2. We also discuss scattering and recombination dynamics of photogenerated electrons and holes on the basis of the time dependence of absorption changes.

Linear and nonlinear optical responses in a molecular crystal, croconic acid, showing electronic-type ferroelectricity were studied by reflection and second harmonic generation spectroscopy. The second-order nonlinear susceptibility χ(2) was very large, exceeding 10−6 esu in the near-infrared region. The enhancement of χ(2) was attributed to the large dipole moment of the lowest π–π* transition and the large difference between the molecular dipole moments for the ground state and the photoexcited state. We deduced the molecular orbitals (MOs) and dipole moments responsible for the large χ(2) by comparing the experimental optical parameters and MO calculation results based upon density functional theory.

The application of microwave-generated atomic oxygen as an oxidant is found to change the manner of atomic layer deposition (ALD) of an Al2O3 layer on a Ge substrate, leading to the spontaneous formation of aluminum germanate with a deposition rate higher than that of conventional ALD with water oxidant. Electrical characterization of the Al/aluminum germanate (11 nm)/p-Ge(100) structure indicates that both the bulk and the interface properties of the aluminum germanate are promising with small capacitance-voltage hysteresis of less than 20 mV and interface trap densities ranging from 2×1011 to 6×1011 cm−2 eV−1 in the upper half of the Ge band gap.

We investigated Fermi-level shifts with carrier doping in La2−xSrxCuO4 (LSCO) (x = 0–0.35) by using heteroepitaxial junctions with Nb–doped SrTiO3. The junctions showed highly rectifying current–voltage characteristics, in accord with the conventional theory of a Schottky or p-n diode. For x = 0–0.20, the built-in potential increased with increase of x, indicating the downward shift of the Fermi-level in La2−xSrxCuO4. The Fermi-level shift however reversed to upward at x ∼ 0.20. This behavior is related to the electronic-structure change, which is characterized by the reversal of dominant carrier type from hole to electron in overdoped La2−xSrxCuO4 confirmed by Hall measurements.

Polarized absorption spectra of hole carriers in rubrene single crystal field-effect transistors were measured in the infrared region (725–8000 cm−1) by charge modulation spectroscopy. The absorptions, including the superimposed oscillatory components due to multiple reflections within thin crystals, monotonically increased with decreasing frequency. The spectra and their polarization dependences were well reproduced by the analysis based on the Drude model, in which the absorptions due to holes in rubrene and electrons in the gate electrodes (silicon), and multiple reflections were fully considered. The results support the band transport of hole carriers in rubrene.

Sub-picosecond modulation of the optical reflectivity (R) using terahertz electric-field (ETHz) pulses was achieved in a typical one-dimensional Mott insulator, the bromine-bridged nickel compound, [Ni(chxn)2Br]Br2 (chxn: cyclohexanediamine). The reflectivity change (ΔR/R) at around the Mott-gap transition peak (∼1.3 eV) was ∼1% for ETHz ∼45 kV/cm, and proportional to the square of ETHz. The relaxation time of ΔR/R was under 0.1 ps, enabling optical switching with a high repetition rate in the near-infrared region. The electric-field and probe-energy dependences of ΔR/R demonstrate that the modulation is due to large third-order optical nonlinearity of one-dimensional Mott insulators.

An electrically active membrane-based mechanical resonator was fabricated from a GaAs/AlGaAs heterostructure. The mechanical motion of the membrane was piezoelectrically excited and detected. The piezoelectric transducer could also excite a range of resonance modes in the membrane that were identified and mapped via optical interferometry. Furthermore, the various mode shapes combined with the piezoelectric transduction could be used to execute mechanical-logic-gates. The development of an electrically active membrane-based mechanical resonator paves the way towards responsive electromechanical detectors and highly functional opto-electro-mechanical systems.

We study the strain-induced voltage generation, i.e., piezovoltage, in a two-dimensional electron system under a magnetic field at low temperature. We find its strong magnetic-field dependence, where the voltage increases up to several microvolts at the boundaries between localized and extended electronic states. The order of magnitude of the generated electrical power is comparable to that of the energy dissipation in mechanical vibration, indicating high-efficiency mechanical-to-electrical energy transduction.

We have investigated the effects of the formation temperature and postmetallization annealing (PMA) on the interface properties of GeNx/p-Ge fabricated by the plasma nitridation of Ge substrates using an electron-cyclotron-resonance-generated nitrogen plasma. The nitridation temperature is found to be a critical parameter in improving the finally obtained GeNx/Ge interface properties. The GeNx/Ge formed at room temperature and treated by PMA at 400 °C exhibits the best interface properties with an interface trap density of 1 × 1011 cm−2 eV−1. The GeNx/Ge interface is unpinned and the Fermi level at the Ge surface can move from the valence band edge to the conduction band edge.

Submicron-scale spatial feature of magnetization reversal dynamics induced by femtosecond optical pulse irradiation in a small external magnetic field was investigated by time-resolved magneto-optical Kerr microscopy on TbFeCo thin film. The magnetization reversal time near the magnetic domain boundary is dominated by an effective magnetic field generated from the peripheral domain by dipole-dipole interaction. The magnetization reversal is accelerated as high as 4.5 times (from 3.4 ns to 750 ps) when reducing the reversed domain size from 1.5 to 0.4 μm due to concentration of dipole-dipole interaction.

We report the ultrafast switching of the magnetic state in the course of photoinduced phase transition from an insulator with short-range charge and orbital order (CO/OO) to a ferromagnetic metal in perovskite-type Gd0.55Sr0.45MnO3. The femtosecond Kerr rotation and reflectivity measurements, which detect the spin and charge dynamics, respectively, have revealed that the metallic state is formed within the time resolution (∼200fs); however, magnetization increases with the time constant of 0.5ps. The relatively slow increase of the magnetization is attributable to the magnetic-field-induced alignment of ferromagnetic domains in the initially produced metallic state.

We demonstrate 1240nm single-photon emissions from InAs quantum dots (QDs) embedded in a hybrid pillar microcavity consisting of dielectric and semiconductor distributed Bragg reflectors. The QDs are grown by metal organic chemical vapor deposition. Discrete emission lines corresponding to isolated QDs in the hybrid pillar are observed with a spontaneous emission rate enhanced by a factor of 2. Single-photon emissions are confirmed by antibunching in a second-order photon correlation function.

Low-dose electron microscopy of radiation sensitive biological specimens achieves only limited resolution because of the inherently weak signal buried in noise. Here, we propose to reduce the noise by using a deformable mirror similar to the Castaing–Henry device to manipulate phase of the electron waves. The method takes advantage of quantum nature of the measurement and nonrandomness of any specimen structure of interest. The simulation revealed 9.7% reduction of noise for the representative case of the ribosome. Increasingly better figures are expected as knowledge about a specimen improves.

Third-order optical nonlinearity was investigated in two charge-transfer (CT)-type conjugated polymers, poly(aryleneethynylene) and poly(thiophene-alt-thiazole), using the third-harmonic generation (THG) method. Comparison of the results with previously obtained THG data for polythiophene and the strong CT polymer poly(thiophene-alt-quinoxaline) revealed that the ratio of the maximum value of third-order nonlinear susceptibility and the absorption coefficient max∣χ(3)∣∕αmax increased as the degree of CT character increased for the four polymers. This variation in max∣χ(3)∣∕αmax is discussed based on the magnitude of the transition dipole moment between the one-photon-allowed and the one-photon-forbidden excited states.

The design and performance of a cryogenic low energy electron point source microscope are described. The microscope can be immersed in liquid helium, thus allowing for investigations at cryogenic temperatures. The cryogenic environment is associated with a low fluctuation in the field emission electron beam current and, combined with a compact and rigid mechanical design, low mechanical drift characteristics.

We have investigated the third-order optical nonlinearity of poly(3-hexylthiophenes) with various head-to-tail coupling ratios (r), using the third-harmonic generation method. An increase in r leads to a reduction in optical gap energy (Eg) and an increase in the third-order nonlinear susceptibility (χ(3)). For r=0 to 0.80, χ(3) is scaled by Eg as χ(3)∝Eg−6.7, while for r∼1, χ(3) is considerably enhanced beyond this scaling law. We discuss how the behavior of χ(3) is based upon the conjugation-length dependence of the transition dipole moments.

An ultrahigh vacuum compatible compact helium cryostat with a 48 h hold time for a 2.5 l of liquid helium capacity has been realized. The design exploits the large enthalpy of the gas phase helium, by using two layers of vapor-cooled radiation shield in place of the conventional liquid nitrogen jacket. The mechanical rigidity, the absence of liquid nitrogen bubbling, and a low helium boil-off rate make this cryostat particularly suitable for applications that require a low vibration environment such as scanning probe microscopy.

The statistical mechanical properties of the systems of athermal multichain (n‐mers) in two‐dimensional lattices are investigated by the computer simulation. The mean dimensions of the chains follow a scaling relation with a scaling variable (n−1)2νn−1φ, where 2ν is the mean square end to end distance exponent and φ is the concentration. The logarithm of the state sum per chain and the osmotic pressure thereof can be described by the same variable in a way which is slightly lattice structure dependent. Because the application of the available theories to our short chain lattice systems may have some controversies, the current coarse graining procedure is appropriately reformulated. The simulation data including the mentioned ones and the chain element distributions around a mass center are well understood by the proposition.

InP epitaxial layers are grown on (100) surfaces of InP substrates by molecular‐beam epitaxy (MBE). Layers grown at a substrate temperature of 450 °C with beam intensity ratio 124P+4/115In+?100 have mirror‐smooth surfaces. Undoped epilayers are n type, with a carrier concentration of 1–3×1016 cm−3 and an electron mobility of 3000 cm2/V sec at room temperature. The photoluminescent (PL) intensity is comparable to that of bulk and liquid phase epitaxial InP, while the intensity of deep‐level emission is smaller than that of them. PL topographs of MBE epilayers are featureless as compared with those of bulk crystals. Deep‐level transient spectroscopy shows three levels of electron trap centers, while hole trap centers cannot be detected.

According to the recent polymer theories, the thermodynamic properties of polymer solutions in a good solvent, at the scaling limit, are governed by a scaling variable composed of the polymerization degree n, the concentration φ, and the polymer dimension exponent ν. Our computer experiments on multichain lattice systems with the nearest‐neighbor interaction afford us the configurational free energy or the osmotic pressure. The nearest‐neighbor interaction or the solvent condition where the free energy best obeys the scaling is reinterpreted as the fixed point solvent condition in a lattice space RG context. We approach the scaling limit by extrapolating the data obtained at that solvent condition to the limit n → ∞. The osmotic pressure obtained by the procedure shows an excellent agreement with Ohta and Oono’s theory. The nonextrapolated chain dimensions at that solvent condition are also in a good agreement with the theory. It is found that a weak nearest‐neighbor attractive interaction works between t...

Computer experiments simulating chain molecule solutions on a tetrahedral lattice have been performed at various concentrations and under several solvent conditions. In good and athermal solvents, mean squares of end to end distance 〈R2〉/b2 and of radius of gyration 〈S2〉/b2 decrease monotonically with the increase in the concentration of chain molecules. In poorer solvents, the monotonic decrease was sometimes not found and in the solutions under very poor solvent conditions, they seemed to have a slight positive dependence on the concentration. The principal moments of inertia of chain molecules were also computed in this connection. The element density distributions around the mass center of a chain were also evaluated and discussed. The numbers of chain element to chain element and chain element to solvent contact pairs, which are closely related to the heat of mixing, were evaluated and compared with the prediction of the quasichemical theory. The agreement was good in good or athermal solvent solutio...

The scaling relations in athermal multichain (n‐mers) systems are reexamined by computer experiments. In the three dimensional space, it is found that the chain mean dimensions and the chain element distributions around a mass center are described by a scaling variable nνd−1φ irrespective of n and the chain concentration φ. The logarithms of the state sum per chain, a kind of the chemical potential, and the osmotic pressures divided by chain number concentrations are found as being described by another variable defined as nνd−1−δφ, where ν is the exponent in the mean square end to end distance vs chain contour length relation, d is the space dimensionality, and δ is a small value. In the two dimensional space, because of the stronger volume exclusion, the value of δ is much smaller and may be 0, as in our earlier paper. A qualitative reasoning based on the picture of the coarse graining is made to interpret the results. It leads us a conclusion that our finding is reasonable in spite of its inconsistency ...

Our numerical experiments aim to study the applicability of the renormalization group (RG) idea to multichain lattice systems. The systems are composed of multiple chains on a simple cubic lattice. The nearest‐neighbor interaction is assumed between nonbonded chain elements. The RG parameter space is spanned by the inverse of the chain length 1/n, the solvent condition η, and the chain number concentration ρ. We first tentatively determine parameter flows by using two RG invariants (weak conditions). Then we examine whether the flows satisfy the RG requirements for the correlations (strong conditions). Simultaneous satisfaction will guarantee us the applicability of the RG idea. We found that the RG idea is applicable to the systems in the very good solvent region but becomes inapplicable to those in the poorer solvent regions and to the shorter spatial distances. In the range where the linearized RG defined by a fixed point in the good solvent region works successfully, we arrive at scaling forms in several fashions. One of them corresponds to Freed’s crossover form. The RG appears to work even in the nonlinear range, i.e., concentrated solutions outside the semidilute region. The RG failure in the poor solvent region is briefly discussed.

High‐resolution transmission electron microscope (TEM) observation is made on cross sections including the growth direction of MBE‐grown AlxGa1−xAs‐AlyGa1−yAs superlattice samples. Lattice images with contrast high enough to distinguish each of the constituent layers in superlattices are important for the study of heterointerfaces on an atomic scale, and two methods are developed in order to obtain them. One is to use superlattices with large difference Δx=y−x in Al composition. It is found that the degree of abruptness at the heterointerface is one or two monolayers and that the heterointerface of the ternary AlGaAs grown on the binary AlAs is smoother than that of the binary grown on the ternary. The other is to observe superlattices by using an electron beam incident along a [100] crystal axis. A theoretical consideration based on both kinematical and dynamical theory of diffraction is given, which suggests that, in obtaining lattice images with high contrast, an electron beam along a [100] crystal axis is more favorable than one incident along the [110] axis which is conventionally used. This is confirmed experimentally by using a GaAs‐AlGaAs superlattice sample.

Vapor‐phase homoepitaxial GaAs films were grown by using the Ga–As–HCl–H2 reaction system under various values of arsenic pressure PAs. Growth rate, electron mobility, shallow donor density ND, shallow acceptor density NA, and deep‐level impurity density NT were measured and found to be in close relationship with PAs. Measurements of the concentration profile NT(x) of the deep‐level impurities in the film were carried out by using the modified version of the transient C‐V method developed by Senechal et al. Main results are (i) The energy level of these impurities is 0.89 eV from the conduction band, which is independent of growth condition, species of substrate and/or the depth position x in the film. (ii) Independently of the occurrence of the abnormal high‐resistivity layer at the film‐substrate interface, the concentration NT(x) in the region within a few microns from the interface is rather lower than that in the region far from it. (iii) In the film grown on the undoped substrate, the density NT(x) ...

Recently reported amorphous polytungstic acids containing peroxo groups are found to provide a new inorganic resist. A homogeneous resist film can be formed easily with the spin coating method. This film is made insoluble in water by deep ultraviolet, x ray, and electron beam irradiation. The oxygen reactive ion etching (O2 RIE) durability is found to be high enough that a bilayer resist scheme employing this resist as a top imaging layer gives a high resolution pattern (line and space: 0.38 μm). The mechanism for the radiation induced reaction is also discussed.

This letter describes the monolithic integration of a laser diode and an optical waveguide modulator that have the same GaAs/AlGaAs quantum well double heterostructure grown on the same substrate. The intensity of the light emitted from the laser diode is modulated by the modulator, utilizing the effect of an electric field on exciton absorption. The absorption loss coefficient of the modulator waveguide with no applied voltage was estimated to be 60 cm−1. This value is much smaller than the previously reported corresponding value of a veguide having a conventional GaAs double heterostructure. The modulation depth achieved was 7 dB for a driving voltage of 2.3 V; the cut‐off modulation frequency was 0.88 GHz. A prospect for improving these characteristics is also presented.

Optical pulses of less than 4 ps full width at half maximum have been generated by electrical gain switching of long‐wavelength multiple quantum well lasers, and were observed directly on a streak camera. This is the first ever generation of optical pulses of such short duration using direct electrical gain switching. We have identified the higher differential gain due to the second quantized state transition in the multiple quantum well laser to be responsible for the generation of these ultrashort optical pulses. We also discuss the possible resolution limits of the streak camera measurement system.

A homogeneous, amorphous peroxopolytungstic acid film can be formed easily with the spin‐coating method. The film is found to provide a homogeneous tungsten metal film after reduction with hydrogen at ∼400 °C. Although the electric resistivity (∼450 μΩ cm) is higher than that for the bulk (5.65 μΩ cm), this method has an advantage in addition to spin coatability: tungsten metal films with fine patterns can be easily obtained because the starting material is photosensitive.

Voltage‐controlled optical bistable laser operation is demonstrated for the first time using nonlinear optical absorption of two‐dimensional excitons in a GaAs‐AlGaAs multiple quantum well (MQW) laser. The laser used here is the conventional MQW laser diode but with tandem electrode configuration. The L‐I curve of light output as a function of current injected into one segment of electrodes can be changed by a bias voltage applied to the other segment of electrodes. At the onset of laser oscillation, a hysteresis loop appears, the shape of which depends strongly on the applied bias voltage. This bistability is ascribed to the nonlinear absorption of two‐dimensional excitons.

We report, for the first time, the spontaneous light emission from ‘‘zero‐dimensional exciton states’’ in GaAs/GaAlAs quantum wells under a high magnetic field at 80 K. The formation of such fully quantized states is evidenced by observing the wavelength shift Δ λ of the spontaneous emission peak as well as the narrowing of the spectrum width as the magnetic field is raised up to 15 T. The observed shift Δλ is shown to be well explained by the theory in which the high magnetic field effect on two‐dimensional hydrogenic exciton is taken into account. The formation of such a novel state is further evidenced by the strong anisotropy of the photoluminescence spectrum, which depends on the direction of the magnetic field.

A comparative study is given of the photoluminescence properties between undoped (100) InP homoepitaxial MBE and LPE films and bulk crystals. All of the samples show two peaks; one is a near band‐edge emission at 1.41 eV with a small shoulder and the other is at about 1.13 eV. It is shown that the MBE films have a near band‐edge emission with intensity comparable with the LPE films, and exhibit a smaller amount of deep‐level emission than the LPE films and bulk crystals.

Lattice deformation and misorientation of InxGa1−xAs epitaxial layers grown on InP substrates by molecular‐beam epitaxy is measured from rocking curves of an x‐ray double‐crystal monochrometer. It is concluded that the epitaxial layers are deformed from cubic to tetragonal and misoriented to the substrates except in lattice‐matched epilayers. This result suggests that the substrate lattice has a large influence on the structure of the epitaxial layers.

The statistical mechanical properties of systems of linear r‐mers (r=4, 5, and 6) in a square lattice space and of those in a two‐dimensional continuous space were studied by Monte Carlo simulations. In the lattice space systems, the site fractions of the 4‐mers ranged from 0.08 to 0.75, those of the 5‐mers from 0.075 to 0.800, and those of the 6‐mers from 0.12 to 0.667. In the continuous space systems, the concentrations were in more narrow ranges. In the lattice space systems, statistical quantities of finite systems were extrapolated to those of infinite systems. Pressures or osmotic pressures of the lattice space systems were close to the Huggins and the Miller–Guggenheim theoretical ones, while pressures of the continuous space systems, in dilute concentrations ranges, were better described by the Flory theory. The occurrence of each conformation of the r‐mers was random in dilute concentration ranges but not in dense ranges. The nonrandomness was much increased in the continuous space systems, especially in the case of the 4‐mers. No sign of the cooperative aligning of the r‐mers was found in the lattice space systems.